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Topic |
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shaktiman
Senior Member
United Kingdom
1226 Posts |
 Posted - 13 May 2002 : 02:53:11
On my Quadra 840av's mobo I have 4 banks of vrams and 4 banks of memory, there is another slot next to the memory with a 2 meg simm installed, is this a level 2 cache? what is a level 2 cache? do I have a level 2 cache? can upgrade this?Where can I get a new pram battery? do I need one to be y2k compliant? is there no software fixes? how much will a pram battery cost? shaktiman |
~Coxy
Leader, Tactical Ops Unit
Australia
2822 Posts |
Posted - 13 May 2002 : 03:15:01
840 AV Mobos aren't my specilaity, but PRAM batteries are!  You can get a batt from any good electronics store. You don't need one to be "Y2K Compliant" - but having one will stop your date and other settings from resetting every time you move it around or have a power strike. There are no software fixes, Macs are already Y2K compliant. A PRAM battery is around $14-$17 AUS, I'm not sure about UK pricing. ~Coxy - Leader, Tactical Operations Unit
Mayor of NuBus City
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SiliconValleyPirate
Junior Member
United Kingdom
273 Posts |
Posted - 14 May 2002 : 15:51:41
Well I took my 840av apart this afternoon to do some hard disk juggling on it. I don't recall there being any more than the 4 VRAM and 4 SIMM slots. However there are solder pads for another slot in front of the RAM SIMMs. It's shorter than the RAM slots (about 60-pins maybe) but I have no idea what it was for if it did have a slot there.--
Mark Benson Visit FlatPackMacs Online
http://fpm.gotdns.com We have feets  Macs Liberated = 10 |
Trash80toG-4
NIGHT STALKER
USA
2899 Posts |
Posted - 14 May 2002 : 18:25:21
quote:
Well I took my 840av apart this afternoon to do some hard disk juggling on it. I don't recall there being any more than the 4 VRAM and 4 SIMM slots. However there are solder pads for another slot in front of the RAM SIMMs. It's shorter than the RAM slots (about 60-pins maybe) but I have no idea what it was for if it did have a slot there.
sounds like about the right pad count for a ROM SIMM, or do you already have one?jt  ™. .
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shaktiman
Senior Member
United Kingdom
1226 Posts |
Posted - 17 May 2002 : 01:20:49
Well whatever it is I have one with a 2mb simm installed.Pirate got it spot on it is where he said and is a touch shorter probably 60 pins. shaktiman |
Trash80toG-4
NIGHT STALKER
USA
2899 Posts |
Posted - 17 May 2002 : 05:01:23
quote:
Well whatever it is I have one with a 2mb simm installed.Pirate got it spot on it is where he said and is a touch shorter probably 60 pins.
here's a diagram of the 840AV mobo, if there's a SIMM slot underneath the DRAM Slots (or above it in the diagram), parallel to the DRAM SIMMS and it's 60 pins it's most likely ROM. the spec on the 840AV's ROM is 2 MB, next time somebody has one open, get the part number for the chips on the SIMM and we'll know for sure. Cache would be at least as wide as the DRAM SIMMS.http://www.macmart.com/rammart/memory/memoryspecs/sheets/quadra840av.html jt ™. .
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SiliconValleyPirate
Junior Member
United Kingdom
273 Posts |
Posted - 17 May 2002 : 17:30:34
quote:
here's a diagram of the 840AV mobo
Ah, it's *labeled* as an 840av logic board but it's not, not by a long stretch. The CPU is wrong, the VRAM slots are too near the front, it has programmers switches at the bottom of the front edge and it has a mystery (PDS/AV?) slot behind the lower NuBus Slot. Nah, that's a Quadra 800 or something, not an 840av. Sadly there is no diargram in the Service Manual so I had to take mine apart (I hope you guys are happy now ). The solder pads are enlosed by a white printed border on the board but are not labeled with a name tag like the Video RAM and the DRAM. Still no idea conclusively but I'll go wioth the flow and say it's a ROM SIMM upgrade slot Apple never used and removed from the board on later models (mine is a 1994 so it's definitely in the later stages of the design's life). --
Mark Benson Visit FlatPackMacs Online
http://fpm.gotdns.com We have feets Wooohoo! I have a green star  Macs Liberated = 10 |
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68k of the Week: kastegir's PowerBook 180.